Field of the Invention
The present invention relates to a display device having an in-cell touch structure and a method of driving the same.
Description of Related Art
In response to the development of the information society, there is increasing demand for various types of display devices able to display images. Currently, a range of display devices, such as liquid crystal display (LCD) devices, plasma display panels (PDPs) and organic light-emitting diode (OLED) display devices, are in common use.
Many display devices provide a touch-based input system enabling users to intuitively and conveniently input data or instructions directly to a device screen, rather than using conventional input systems, such as buttons, a keyboard, or a mouse.
In order to provide such a touch-based input system, sensitivity to the touch of a user and the ability to accurately detect coordinates of a touch point are required.
In this regard, the related art provides touch sensing systems using a touch sensing method selected from among a variety of touch sensing technologies, such as resistive touch sensing technology, capacitive touch sensing technology, electromagnetic induction technology, infrared (IR) touch sensing technology and ultrasonic touch sensing technology.
Among the variety of touch sensing technologies, capacitive touch sensing technology is most commonly used. This technology uses a plurality of touch electrodes (e.g. row electrodes and column electrodes) disposed on a touchscreen panel to detect a touch and coordinates of a touch point based on changes in capacitance between touch electrodes or between a pointer, such as a finger, and a touch electrode.
According to capacitive touch sensing technology, in addition to capacitance necessary for touch sensing, undesirable parasitic capacitance is generated by other voltage lines or electrodes surrounding touch electrodes.
Such undesirable parasitic capacitance causes certain problems, for example, increasing the load of a touch operation, decreasing the accuracy of touch sensing, and in severe cases, making touch sensing impossible.
The problems caused by parasitic capacitance become more severe in medium-sized or larger display devices.
The problems caused by the undesirable parasitic capacitance frequently occur in in-cell display devices inside which a touchscreen panel (TSP) is integrally provided using “in-cell” technology, even causing the realization of medium-sized or larger in-cell touchscreen panels to be impossible.